diff --git a/src/mode/fdm/export.js b/src/mode/fdm/export.js
index 38fd9198..0545726d 100644
--- a/src/mode/fdm/export.js
+++ b/src/mode/fdm/export.js
@@ -61,7 +61,7 @@
             lineWidth = process.sliceLineWidth || 0,
             seekMMM = process.outputSeekrate * 60,
             retDist = process.outputRetractDist || 0, // range
-            retSpeed = process.outputRetractSpeed * 60, // range
+            retSpeed = process.outputRetractSpeed * 60 || 1, // range
             retDwell = process.outputRetractDwell || 0, // range
             timeDwell = retDwell / 1000,
             peelGuard = process.outputPeelGuard || 0,
@@ -117,7 +117,7 @@
             let process = getRangeParameters(settings, layer);
             zhop = process.zHopDistance || 0; // range
             retDist = process.outputRetractDist || 0; // range
-            retSpeed = process.outputRetractSpeed * 60; // range
+            retSpeed = process.outputRetractSpeed * 60 || 1; // range
             retDwell = process.outputRetractDwell || 0; // range
             timeDwell = retDwell / 1000;
             nozzleTemp = layer === 0 ?
diff --git a/src/mode/fdm/slice.js b/src/mode/fdm/slice.js
index 7d3d501d..9a4ac88b 100644
--- a/src/mode/fdm/slice.js
+++ b/src/mode/fdm/slice.js
@@ -334,7 +334,7 @@
                 let minx = Infinity, maxx = -Infinity;
                 let peek = 0;
                 for (let slice of slices) {
-                    if (slice.groups.length && peek++ < 5) {
+                    if (slice.tops.length && peek++ < 5) {
                         for (let poly of slice.topPolys()) {
                             minx = Math.min(minx, poly.bounds.minx);
                             maxx = Math.max(maxx, poly.bounds.maxx);